//#pragma comment(linker,"/STACK:16777216") /*16Mb*/
//#pragma comment(linker,"/STACK:33554432") /*32Mb*/
#define _CRT_SECURE_NO_DEPRECATE
#include<iostream>
#include<numeric>
#include<sstream>
#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<memory>
#include<string>
#include<vector>
#include<cctype>
#include<list>
#include<queue>
#include<deque>
#include<stack>
#include<map>
#include<set>
#include<algorithm>
using namespace std;

typedef unsigned long long      ui64;
typedef long long               i64;
typedef	vector<int>             VI;
typedef	vector<bool>            VB;
typedef	vector<VI>              VVI;
typedef	vector<string>          VS;
typedef	pair<int,int>           PII;
typedef map<string,int>         MSI;
typedef set<int>                SI;
typedef set<string>             SS;
typedef map<int,int>            MII;
typedef	pair<double,double>     PDD;

#define PB                      push_back
#define MP                      make_pair
#define X                       first
#define Y                       second
#define FOR(i, a, b)            for(int i = (a); i < (b); ++i)
#define RFOR(i, a, b)           for(int i = (a) - 1; i >= (b); --i)
#define CLEAR(a, b)             memset(a, b, sizeof(a))
#define SZ(a)                   int((a).size())
#define ALL(a)                  (a).begin(), (a).end()
#define RALL(a)                 (a).rbegin(), (a).rend()
#define INF                     (2000000000)


int main()
{
	int n;
	cin >> n;
	VVI a(n,VI(n));
	FOR(i,0,n) {
		FOR(j,0,n) {
			cin >> a[i][j];
		}
	}
	int ans = 0;
	FOR(i,0,n) {
		//calc from i to i+1
		int tans = 0;
		FOR(j,0,n) {
			FOR(k,0,n) {
				if( j<=i && k>i ) {
					tans += a[j][k];
				}
			}
		}
		ans = max( ans, tans );
	}
	RFOR(i,n,0) {
		//calc from i to i-1
		int tans = 0;
		FOR(j,0,n) {
			FOR(k,0,n) {
				if( j>=i && k<i ) {
					tans += a[j][k];
				}
			}
		}
		ans = max( ans, tans );
	}
	cout << ans/36 + (ans%36?1:0) << endl;
    return 0;
}